This invention is generally directed to new organic sulfate and sulfonate compositions and process for the preparation of such compositions. More specifically the present invention is directed to certain toluene sulfonate and sulfate compositions which are useful as charge enhancing additives for electrostatographic developer compositions comprised of toner particles and carrier particles. Thus, for example, toner compositions containing the sulfates and sulfonates of the present invention are useful in electrostatographic imaging systems wherein the imaging member is charged negatively, and further such compositions are useful in imaging systems containing a Viton fuser roll as more specifically detailed hereinafter.
Described in a copending application U.S. Ser. No. 212,969, filed Dec. 4, 1980, are toner compositions containing the organic sulfate and sulfonate compounds of the present invention. The disclosure of the copending application is totally incorporated herein by reference.
Various sulfate and sulfonate compositions are known including, for example, ammonium lauryl sulfate, sodium xylene sulfonate, sodium dodecyl benzene sulfonate, triethanol amine dodecyl benzene sulfonate, cetyl trimethyl ammonium para-toluene sulfonate, sodium tetradecyl sulfate, and the like. These materials are, for example, useful as surfactants, anti-static additives for toiletry preparations, and the like. There continues to remain a need, however, for new sulfates and sulfonates, particularly those which are useful as charge enhancing additives. The need for these additive, especially those which impart a positive charge to the toner resin has experienced a recent growth in view of the desire to use negatively charged photoresponsive imaging devices in electrostatic imaging systems.
Various charge control additives are disclosed in the prior art, thus for example, there is disclosed in U.S. Pat. No. 3,893,935 the use of certain quaternary ammonium compounds as charge control agents for electrostatic toner compositions. According to the disclosure of this patent, certain quaternary ammonium compounds when incorporated into toner materials were found to provide a toner composition which exhibited relatively high uniform and stable net toner charge when mixed with a suitable carrier vehicle. A similar teaching is contained in U.S. Pat. No. 4,079,014 wherein a diazo toner charge control additive is described. Further, there is disclosed in U.S. Pat. No. 4,298,672 as charge enhancing additives alkyl pyridinium compositions including cetyl pyridinium chloride.
Many of the above disclosed charge control materials interact with certain fuser rolls, such as Viton fuser rolls, used in electrostatographic systems. This interaction causes these fuser rolls to be adversely affected, resulting ultimately in a deterioration of image quality. For example, the Viton fuser rolls discolor and turn black, as well as develop multiple surface cracks when certain charge control additive compounds are employed in the toner mixture.
One Viton fuser roll selected for electrostatographic devices, particularly xerographic imaging systems, is comprised of a soft roll fabricated from lead oxide and duPont Viton E-430 resin (a vinylidene fluoride, hexafluoropropylene copolymer). This roll can be prepared by blending together, and curing at elevated temperatures approximately 15 parts of lead oxide, and 100 parts of Viton E-430. Apparently the function of the lead oxide is to generate unsaturation by dehydrofluorination for cross-linking, and to provide release mechanisms for the toner compositions. Excellent image quality has been obtained with the use of Viton fuser rolls, however, in some instances, there is a toner-fuser compatibility problem when charge control substances are contained in the toner mixture. It appears that certain charge control additive, such as quaternary ammonium compounds, and alkyl pyridinium compounds react with the Viton fuser roll. For example, cetyl pyridinium chloride when part of the toner mixture appears to be catalytically decomposed by the lead oxide in the fuser roll, resulting in a highly unsaturated compound, which polymerizes and condenses with the unsaturated Viton. As a result, the Viton fuser turns black and develops multiple surface cracks, thereby resulting in image quality deterioration.